Maps Designed to Stop Gas Explosions—and Help the Climate

Last March’s gas explosion in East Harlem—which killed eight people and obliterated two buildings—was an awful consequence of a too-common problem: old, leaking pipes, which lie beneath countless major U.S. cities.

And in addition to causing tragic blasts, tattered lines are also culprits in an even greater health threat: global warming. Methane, the major component in natural gas, is extremely effective at absorbing and trapping the sun’s heat.

Yet few cities are fixing their buried, ticking bombs. Why? For starters, pipelines are poorly regulated by the government. Repairing them is also expensive for local utilities, who are usually the financially responsible party. And even locating the leaks (before it’s too late) can be arduous work, requiring lots of workers and heavy equipment to suss them out.

But that last barrier could soon be lowered, thanks to the Environmental Defense Fund’s new interactive maps, which visualize seepage spots in three cities so far. The EDF teamed up with Google Earth Outreach, Google’s nonprofit-partnership arm, for the project. Google equipped their usual street rovers—the same ones that capture images from the world’s streets, oceans, and even museums—with air-quality sensors that detect methane concentration, wind speed and direction, and GPS location. They patrolled the streets of three cities in areas serviced by each metro’s major gas utility.

In Boston, a city where half the pipes are at least 50 years old, leaks were detected about once every mile.

Most of the seeping spots were marked “low” on the methane-leak indicator, which means they release gas at a rate of 700 to 9,000 liters per day. That kind of output has roughly the same immediate impact on the climate as a car that’s traveling 100 to 1,000 miles in a day. A few spots in Boston marked as “high” seeped at more than 60,000 liters per day—the equivalent of a car traveling more than 9,000 miles in a day.

Staten Island, where most pipes are also more than a half-century old, was also riddled with leaks. Its map reflects these, as well as a high background level of methane, probably due to the island’s enormous Fresh Kills Landfill.

The third city, Indianapolis, relies on a public trust instead of a private utility to distribute natural gas. After a gas explosion killed two people in the early 1980s, the trust, called Citizens Energy, invested in replacing the bulk of their old, corrosive pipes with modern ones. The difference is stark.

This project is significant not only because of its novel visualization strategy, which the EDF hopes will spur the public to advocate for the same in their own cities. It has also captured the actual rate of leakage at the spots surveyed, which previous detection methods had not. That gives climate scientists a better understanding of how much methane is filling the atmosphere, and gives city policymakers a clear starting point for repairs.